1. Field of the Invention
This invention relates generally to a method and apparatus for use in well drilling equipment, and, more particularly, to a method and apparatus for controlling the loading of drill pipe and/or casing through a door in a pipe shelter of the well drilling equipment.
2. Description of the Related Art
The progress of the industrial era is based, in significant part, on the discovery and useful application of hydrocarbon fuels. Increasing industrialization of the world has lead to corresponding growth in the need for and use of these hydrocarbon fuels. Given a finite supply of hydrocarbon resources, it should be appreciated that the resources that are most readily accessible, and, correspondingly, the least expensive to produce, have been discovered and exploited on a large scale.
As demand for the hydrocarbons increased, so to did the price, thereby encouraging exploration and production into previously economically infeasible areas of the world. For example, rising prices were accompanied by exploration and production from offshore platforms and ships that drilled into the ocean floor. The technical difficulty and attendant expense of such offshore drilling is readily apparent.
Additionally, huge oil reserves have recently been discovered, and production has begun in what is arguably the most severe climate on the planet, the arctic, or the North Slope of Alaska. While the technical difficulties faced in such an environment are far different than those experienced on offshore platforms, they are, nonetheless, severe to the point of rendering equipment commonly used elsewhere useless.
A problematic area, if not the most significant difficulty, in drilling oil wells on the North Slope, is, of course, exposure of the equipment and work force to arctic temperatures. Outdoor temperatures often reach -70.degree. F., whereas minimally comfortable temperatures for the work force begin at more than 100.degree. F. higher. Providing a comfortable work environment is known to dramatically improve the efficiency of the work force.
Further, it is preferred that casing and/or drill pipe used in drilling a well should be substantially free of dirt, ice, snow, etc., especially adjacent their threaded end regions. Ice present on the threads of the pipe and/or casing can cause the threads to be stripped or at least damaged during the connection process. Clearly, removing ice or snow from the pipe and/or casing is significantly easier in a heated environment.
While it is readily possible to heat enclosed structures to such a desirable temperature, the problem lies in the continuous need for large, bulky items to be used in the drilling process, i.e., drill pipe and casing. Accordingly, closed structures associated with the drilling equipment, such as a pipe shelter, are frequently and continuously opened to the elements so that pipe and casing may be loaded therein. The large, bulky nature of the pipe and casing necessitates that the door or opening through which the pipe and casing are loaded must also be large, thereby causing a significant exchange of heated air for arctic air. Thus, the temperature of the pipe shelter is difficult to maintain at a comfortable working temperature.
The present invention is directed to overcoming or at least minimizing one or more of the problems set forth above.